Understanding the transcriptional programs that define cell type and regulate the inflammatory responses in macrophages and vascular endothelium is of central interest in understanding/preventing prevalent cardiovascular diseases. The molecular strategies that dictate these critical transcriptional programs reflect, in large part, the actions of dedicated repression "checkpoints" and the functions of enhancers that modulate cell type-specific gene expression programs. How the programs dictated by an enhancer "code" underlying such programs remains a fundamental question in regulatory and cardiovascular biology. Our studies under this Grant have linked integration of inflammatory and anti-inflammatory signaling pathways and inhibiting atherosclerosis, uncovering functionally-distinct pathways utilized by PPAR3 and LXRs, and provided initial insights into the large programs of transrepression critical for blocking inflammatory pathways. Here, we will use genetic and epigenetic approaches to uncover the in vivo roles of dedicated enhancer networks in cardiovascular disease. We propose to focus on the molecular determinants of cell type-specific gene enhancer programs and three-dimensional genomic interaction networks that underlie developmental and newly discovered regulatory programs in the cardiovascular system and macrophages. We will link these programs to two important myocardial infarction susceptibility loci, based on results from genome-wide association studies (GWAS), providing an unprecedented opportunity, based on human genetic models, to further define and delineate the role of three-dimensional "enhancer networks" and epigenetic strategies in development and disease of the cardiovascular system. These studies should provide a general approach to investigating disease susceptibility loci for many classes of disease. PUBLIC HEALTH RELEVANCE: Coronary artery disease, the predominant cause of myocardial infarction, is caused by coronary artery atherosclerosis, with an estimated 1.5 million Americans experiencing a coronary attack/infarction in 2009. Because atherosclerosis reflects both inflammatory and lipid metabolism disorder in which monocytes/macrophages play a central role in all phases of atherosclerosis, our proposal to link the discovery of the key regulated "enhancer codes" in tissues that underlie cardiovascular disease and regulation of their nuclear architecture to genome-wide association studies of susceptibility to coronary artery disease can provide new insights and approaches to the prevention and treatment of this major disease of the cardiovascular system.